1. Field
The present invention relates to electronics and, more specifically but not exclusively, to Doherty amplifiers.
2. Description of the Related Art
This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
A Doherty amplifier has a main amplifier branch and one or more peak amplifier branches that are configured to assist the main amplifier branch in the amplification process when the applied input signal is relatively large. At relatively low input signal levels, the peak amplifier branches are inactive, and amplification is performed only by the main amplifier branch. In conventional Doherty amplifiers, the input signal level at which a peak amplifier branch becomes active is controlled by appropriately biasing the transistor(s) used to implement the branch's peak amplifier. Such biasing imposes a tradeoff between gain and linearity on the one hand and efficiency on the other, such that increased gain and linearity are achieved at the expense of lower efficiency, and vice versa.